To be honest, having a lot of altcoins is not that safe at all. There's more risk to that and I have proven that to myself. I'd rather go with fewer cryptos in my portfolio than to be diversified a lot. Someone who owns bitcoin only can outperform those who has diversified a lot with their investments and as well as those who trades a lot. While that person with bitcoin or other few altcoins, they have nothing to worry with thinking of where to diversify because they have already maintained the risk that they're taking and at the same time maximizes potential profit.
Holding Altcoins alone is a risk on its own let alone holding so many. I’m not really a fan of altcoins, I believe it’s a lot more safer to hold Bitcoin, but if you must hold altcoins, it should be the likes of ETH that have been proven to have passed the test of time and have survived through the market’s thick and thin cycles. But the overall advise given to people who wish to hold assets or invest in crypto, be it altcoins or bitcoin, it is to only risk what one can actually afford to lose, because the market can be volatile and losses can be easily incurred, especially when you’re investing for the short term.
I concur that it's safer to hold bitcoin because that's where I have profited the most. I've held several altcoins but most of them only gave me losses. And from that personal experience, I have minimized the buying of altcoins and went focused and allotted more of my budget to bitcoin and I have never been happier when I did that.
Due to not good enough development in crypto market now things are getting worst for investors specially those are having mind their investment will be bring good profit for them in near future but they are not able to recover because strategy not working and mostly cryptocurrencies are going down badly just relaying on few coins are having some benefit but trying to go blindly in many coins always increase loses. Currently Bitcoin is doing enough good just because of these few coins that are also having a good increase in value but still mostly are on dead level now. I mostly encourage people to stay with Bitcoin, but in case someone wants to go ahead in crypto, usually try to have coins in top ranks because they are doing better and have a chance of giving a good response in the near future as well.
IMHO to these investors who are in that situation, they need to change their choices and decisions. Because I have seen enough from those who don't like to own bitcoin and it just keeps on proving them wrong and they need to have it for their portfolios to balance if ever they have some alts on hold and majority of it are going down.